WO2000048850A1

WO2000048850A1 - Reinforcing ply for tyre, method for making same and method for making a tyre

Info

Publication number: WO2000048850A1
Application number: PCT/EP2000/001189
Authority: WO
Inventors: Jean Billieres
Original assignee: Societe De Technologie Michelin; Michelin Recherche Et Technique S.A.
Priority date: 1999-02-19
Filing date: 2000-02-14
Publication date: 2000-08-24
Also published as: BR0008349A; EP1154906B1; KR100605239B1; CN1341058A; CN1253324C; JP2002537162A; EP1154906A1; DE60038952D1; FR2789941A1; FR2789941B1; US20020046795A1; CA2362837C; KR20010102096A; US6941993B2; RU2250836C2; CA2362837A1; JP4568435B2

Abstract

The invention concerns a tyre having at least one reinforcing ply (1, 31, 32) consisting of reinforcing elements embedded in vulcanised rubber, characterised in that said ply reinforcing elements are individually coated with a rubber mixture (B, B1), said coating mixture having a composition and specific physical properties, said reinforcing elements arranged mutually parallel being coated on one surface with a first rubber mixture (A, A1), called first skim coat, of constant composition and properties, whereas said elements are coated on the opposite surface with a second rubber skim coat (C, D) of composition and properties varying according to the meridian position on the ply in the tyre.

Description

Reinforcement ply for tire, its manufacturing method and method of manufacturing the tire

The present invention relates to a reinforcement ply for a tire, as well as to the tire using such a ply as reinforcement. It also relates to the method of manufacturing such a ply, as well as the method of manufacturing the tire which uses said ply.

A reinforcing ply for a tire is formed of reinforcing elements generally covered on either side with layers of rubber mixture called calendering layers, so that said elements cannot be in contact with the outside. The rubber mixture used is generally unique, with the same composition and the same properties.

It is sometimes highly desirable that the calendering mixture be different for the same ply according to the location of said ply in the tire which uses it, whether it is a carcass reinforcement ply, a crown reinforcement ply, or any other reinforcement ply. According to the teaching of patent FR 2 351 810, a crown reinforcement with several plies of reinforcing elements, mutually parallel in each ply and crossed from one ply to the next, must be provided, in order to increase the duration life of the tire, with different characteristics in its central zone and its marginal zones. The tire of said reference, comprising a carcass reinforcement and a crown reinforcement of several plies, is characterized in that the rubbery calendering mixture of the crown plies has a modulus of elasticity in tension at 100% elongation greater than 70 kg / cm ² in the median zone of the crown reinforcement, zone defined by the ratio of the width of said zone to the overall width of said reinforcement, and in that the rubbery calendering mixture of the same plies has a module of elasticity in tension at 100% elongation less than 40 kg / cm ² in the two remaining marginal zones of the crown reinforcement.

The teaching of patent FR 1 331 934 relates to a tire with a radial carcass reinforcement, and the invention described consists in stiffening the lower part of the sidewalls, by giving them a more attenuated rigidity than the commonly used solution allows, it that is to say the laterally superimposing of crossed cables on the radial carcass reinforcement. To this end, the stiffening of the flanks, in the zone between the bead and substantially the mid-flank, is obtained by means of at least one ply of meridian reinforcing elements coated in the calendering mixture of the reinforcement of carcass. In one of the embodiments described, the carcass reinforcement consists of a single ply of radial metallic wires or cables, turned around the rod and stopping in the bead, these wires or cables being coated in the area included between the bead and substantially the mid-side of calendering layers whose modulus of elasticity is at least 350 g / mm ² , which module is a high modulus relative to the modulus of the remaining calendering mixture.

Document FR 2 075 851 recalls that. in certain tires with a radial carcass reinforcement, the choice of the connecting rubber between the reinforcing elements is an essential factor in the appearance or not of certain defects after rolling of the tire. Thus, the choice of a bonding rubber with a low modulus of elasticity promotes the separation of the carcass reinforcement cables at the end of the inversion of said reinforcement, in the beads and in the flank regions adjacent to the beads, more especially for the carcass ply which has a high upturn in the sides. Furthermore, the choice of a bonding rubber with a high modulus of elasticity favors the tearing of the bonding rubber between carcass reinforcement cables, along the radial lines in the upper region of the flanks. To obtain the best results, patent FR 2 075 851 recommends, more particularly for tires with a radial carcass reinforcement, to surround the cables in relatively elastic material, with a layer of coating rubber with relatively high modulus of elasticity, the said cables being separated by an interstitial rubber mixture which has a relatively low modulus of elasticity in the upper region of the flanks and relatively high in the lower region of the flanks, coating layer and interstitial layer having the same modules in the lower zone. As for the process for obtaining that in the upper flanks area the cable coating rubber and the interstitial rubber between cables of the same ply are of different qualities, whereas they are identical in the low zone, it consists, during the manufacture of the tire, to have radially inside a ply, calendered cables in a layer of first quality rubber, a layer of second quality rubber, and during the vulcanization of the tire to exert a tension on carcass reinforcement cables.

Whether it is one or the other of the previous solutions, whether for carcass reinforcement or for crown reinforcement, the methods used to obtain a reinforcement ply as described do not allow, given the multiple dispersions affecting the quality of the semi-finished product that is the tablecloth in the unvulcanized state, to obtain the optimal structure of said tablecloth according to whether it is used in carcass reinforcement or in crown reinforcement, and even less its effective use during manufacturing a tire.

The invention aims to remedy these drawbacks. It proposes a tire having at least one reinforcement ply made up of reinforcement elements embedded in vulcanized rubber, characterized in that the reinforcement elements of said ply are individually coated in a rubber mixture, said coating mixture, having a composition and given physical properties, the said reinforcing elements arranged parallel to each other being covered on one face with a first rubbery layer, called the first calendering layer, of constant composition and properties, while the said elements are covered on the opposite face with a second rubberizing calendering layer. of variable composition and properties as a function of the meridian position on the reinforcement ply in the tire.

The composition and properties of the first calendering layer may be identical to the composition and properties of the coating mixture of the reinforcing elements. Advantageously, said composition and properties of the first layer will be different from those of said coating mixture.

The reinforcing ply may be a carcass reinforcement ply, for example radial, the reinforcing elements of which may be metallic and / or textile: the meridian position is then judged on the meridian length of the ply. The reinforcement ply may be a crown reinforcement ply, for example formed of reinforcing elements which are parallel to each other in said ply and forming an acute angle with the circumferential direction of the tire, or formed of circumferential elements. the meridian position judging on the axial width of said ply. It can also be any other reinforcement ply commonly or very often used in tires, such as bead reinforcement plies, sidewall reinforcement plies, the meridian position then being able to be assimilated to a radial height.

The process for manufacturing the unvulcanized reinforcement ply necessary for obtaining the ply according to the invention, as a semi-finished product, consists in first of all manufacturing an intermediate product called "one-side calendered ply", obtained by individual coating of several reinforcing elements with a rubbery mixture by means of an extruder with several dies, followed by the arrangement using a suitable means said coated elements along parallel lines, respecting a defined spacing between two adjacent elements, one of the faces of the set of coated elements obtained being provided with a first non-vulcanized calendering layer also called support layer, by placing said calendering layer in contact with said assembly.

The said calendering layer is brought into contact with all of the coated reinforcing elements can be done either by simple laying of the assembly on the calendering layer. either by simple laying of the calendering layer on the set of reinforcing elements, but preferably in both cases with the application of a light pressure on one or both components that are the set of elements and the calendering layer.

The unvulcanized “one-sided calendered sheet” can be used with reinforcement elements individually coated in a rubber mixture, either unvulcanized or pre-vulcanized. The method relating to the second possibility comprises an additional step consisting in pre-vulcanizing the coating mixture at a given temperature using a suitable heating means.

The "calendered sheet on one side", obtained continuously, can be wound on itself, as known per se, by means of an intermediate layer either of fabric or of polyethylene for example serving as an anti-adhesive. to form tablecloth rolls. Said rollers are used to feed a tablecloth preparation table depending on whether they are carcass plies or crown plies. As known per se. the preparation of a carcass ply requires a cutting of the reinforcing elements perpendicular to their common direction so as to obtain the desired meridian length, while the preparation of a crown ply requires a cutting of the reinforcing elements at a certain angle and the butting of the portions of ply obtained to lead to the desired circumferential length of the crown ply.

The manufacture of the reinforcement ply, intended for use in the tire, is completed and terminated by the addition, on the second face of "the calendered one face ply" of coated and cut reinforcement elements, of the second layer calendering. said second layer having no constant composition and properties. Said addition can be done in several ways:

- either by bringing the "calendered sheet on one side" into contact, after cutting, with the second calendering layer of composition and properties which vary according to the meridian position, layer previously prepared, for example, on an apparatus independent of the cores or drums for making and / or finishing unvulcanized blanks for carcass reinforcement and / or tires (for example a tablecloth preparation table), said contacting being able to be carried out either by laying the "calendered tablecloth a face "on the second calendering layer. either by placing said second calendering layer on the appropriate face, the side where the reinforcing elements coated with the "calendered one-sided sheet" appear, said second layer possibly being in the form of strips of mixtures with different composition and properties of a strip to the strip which is axially adjacent, or in the form of a single layer of mixture in which the transition from one strip composition to another strip composition takes place gradually, and / or continuously;

- or preferably by bringing the "calendered sheet on one side" into contact, after cutting, with the second calendering layer of composition and properties which vary according to the meridian position, layer prepared on the apparatus used for making and / or finishing of blanks not vulcanized carcass reinforcement and / or tires (cylindrical drum for making a carcass reinforcement blank, drum for finishing the tire blank in toric form), said contacting being able to be carried out either by laying of the face of the "calendered sheet one face" where the coated reinforcing elements appear, on the second calendering layer initially placed on the unvulcanized blank during manufacture, or by laying the second calendering layer on the " one side calendered sheet "predisposed on the blank during manufacture, said second layer being able to take the two forms mentioned above.

The characteristics of the invention will be better understood with the aid of the description which follows and which refers to the drawing, illustrating non-limiting examples of execution, drawing in which:

FIG. 1 schematically represents, seen in meridian section, a tire comprising crown plies and a carcass ply according to a variant of the invention,

* Figure 2 is a schematic sectional view along AA, while

FIG. 3 is a schematic sectional view along BB,

FIG. 4 schematically represents, seen in meridian section, a crown reinforcement composed of two layers,

* Figure 5 shows schematically the different stages of manufacturing a "calendered sheet one side". The tire, shown in FIG. 1. is a tire of the “Heavy” type of small dimension 9.00 / 20 X. It is made up of a radial carcass reinforcement, formed of a single ply (1) of elements reinforcement, in this case inextensible metal cables, anchored in each bead to an annular bead reinforcement element, in this case a rod (2), to form a reversal (10). Said carcass reinforcement is radially surmounted by a crown reinforcement (3). composed on the one hand, of two working crown plies (31, 32), formed of inextensible metallic cables parallel to each other in each ply and crossed from one ply (31) to the next (32) while making with the direction circumferential angles between 10 ° and 45 °. and in the case described respectively equal to 26 ° and 18 °. and on the other hand, radially on the outside, of a ply of elastic metallic cables oriented with respect to the circumferential direction at the same angle as the angle of the cables of the working crown ply (32) most outside. The crown reinforcement (3) is joined radially to the carcass reinforcement (1) by a layer (8) of rubber mixture of constant thickness in the central part, and of increasing thickness going along the edges of the crown reinforcement (3). Said crown reinforcement (3) is radially surmounted by a tread (9), joined on either side of the equatorial plane to a mixture of sidewall (7), covering, in the sidewall of the tire, the frame carcass (1) and ensuring the junction, on the one hand with the mixtures (40, 41, 42) reinforcing the bead and. on the other hand with the mixture (1 1) ensuring the protection of said bead and contact with the service rim. An inner coating layer (5) of the pneumatic cavity and various rubber reinforcements between said layer and the carcass reinforcement complete the tire.

The carcass reinforcement ply (1) is. in the example described, formed of inextensible steel metallic cables coated in a mixture of rubber B, the composition of which is adapted so that said mixture in the vulcanized state adheres perfectly to the brassy layer covering the steel of the reinforcing cables. Said cables coated with mixture B are calendered, over the entire meridian length of the outer side of the carcass ply (1), including the carcass ply upturns, by a layer of rubber mixture A. first calendering layer or layer support, because it is the layer on or under which the carcass ply cables are laid during the manufacture of the "one-side calendered ply". As for the inner calendering layer of the ply (1), which is the second calendering layer C, it is formed by several bands or circumferential layers of rubber mixtures of different composition and qualities from one band to the adjacent band, the composition and properties of a strip being chosen according to the meridian position of said strip on the meridian length of the carcass: from point T of the rod (2) radially closest to the axis of rotation, at point S d ' intersection between the mean axis of the meridian profile of the carcass ply (1) and the perpendicular to said lowered profile of the end of the ply upturn (10), the TS zone being called bead zone, the layer C consists of a first strip Ci of rubber mixture. Said point T at point R representing the end of the upturn (10) of the carcass ply (1), the zone TR being known as the inversion zone, the layer C consists of a second strip C ₂ of rubber mixture (FIG. 2 shows the different layers in the area of the tire bead). Between point S and a point N of intersection of the mean axis of the meridian profile of the carcass ply (1) with a straight line parallel to the equatorial plane and distant from said plane by an amount which can be between 30% and 45% of the axial width of the tread (9). in the case described equal to 35% of said width of the tread, the zone SN being said flank and shoulder zone, the layer C consists of a third band C ₃ of rubber mixture. Between the point N and the equatorial plane XX 'forming the so-called apex zone, the fourth mixing strip C ₄ forms the layer C.

In the example shown in Figures 1 to 3. the layers or bands A. B, C ,, C ₂ and C ₄ are formed from the same rubber mixture which. in the vulcanized state. has a secant modulus of elasticity in tension, measured under a relative elongation s equal to 0.1. (the modulus thus defined is determined in accordance with standard AFΝOR-ΝF-T46-002 under normal conditions of temperature and hygrometry according to standard AFNOR-NF T40-101. and will be in the rest of the description more simply called module) is between 6 MPa and 12 MPa. while the mixture of the layer C ₃ of calendering of the carcass ply part (1) in the flank and shoulder area consists of a rubber mixture whose module of the same name and measured under the same conditions is significantly lower, since between 3.5 MPa and 5 MPa. The first mixture above has, in the unvulcanized state, a fairly high Mooney viscosity, between 60 UM and 90 UM, while the mixture of layer C ₃ has a viscosity of the same name lower since between 55 UM and 75 MU (the Mooney viscosity being measured in accordance with standard AFNOR-NF-T43-005).

For another dimension of tire, and depending on the endurance damage encountered on such a dimension, the coating layer B will be produced with a mixture with very high modulus, between 27 MPa and 45 MPa. and with a very high Mooney viscosity of between 70 UM and 100 UM, while the support layer A will consist of a mixture with a lower modulus than the previous one, but nevertheless high because between 10 MPa and 15 MPa, and with a viscosity Mooney herself bred and between 60 CU and 90 CU. The layer Ci will consist of the same mixture as the layer A; on the other hand, the layer C ₂ will be a mixing strip whose modulus is low, since it is understood between 3.5 MPa and 5 MPa. and of lower Mooney viscosity between 55 MU and 75 MU. mixture which will also be that of band C ₃ . while the layer C ₄ will be produced with a mixture of intermediate module, between 6 MPa and 12 MPa. and of viscosity between 60 MU and 90 MU.

Another beneficial solution consists in choosing as a rubbery mixture of the support layer A a mixture of low modulus of elasticity in the vulcanized state, and of using the said support layer as calendering inside the carcass ply (1). , the layers CC ₃ , and C ₄ then forming the layer C for external calendering of the carcass ply (1). The mixture of layer B will be identical to that of the previous example, the mixture of layer A will be the mixture constituting layer C of the previous example with a module of between 3.5 MPa and 5 MPa. and a viscosity of between 55 MU and 75 MU. From a point U of the carcass ply upturn, located radially approximately halfway up said upturn (10) at point S previously described, passing under the bead wire (2), the strip C'i is formed from a mixture with high modulus of elasticity between 10 MPa and 15 MPa, and high viscosity between 60 UM and 90 UM, whereas from said point U to point R of the turning end (10), the strip C ₂ will be formed of the same mixture as that constituting the support layer A. It is the same for layer C ' ₃ from point S to point N, while layer C will be formed of the same mixture as that constituting layer C ₄ of the previous example .

It is not going beyond the ambit of the invention if the layer C, whether it is an interior or exterior calendering, is obtained by winding a strip of rubber mixture, the composition and properties of which vary continuously, and / or the passage or transition from a mixture composition in a carcass ply zone to the mixture composition in an adjacent zone takes place gradually (for example passage of the mixture forming the layer C ₃ to the mixture forming layer C): the strip for forming layer C can be obtained, as known per se, by kneading and / or mixing on a grinder-mixer of one or two quantities of rubber granules (in the example chosen, granules of the two mixtures forming the layers C ₃ and C); the mill-mixer being fed from several hoppers each containing a rubber mixture of composition and properties given in the form of granules, and the desired quantities being obtained by the opening of feed chutes, opening governed by control valves feed, which makes it possible to obtain a transition zone between the layers C ₃ and C ₄ where the mixture forming C ₃ gradually changes composition to become the mixture forming C ₄ .

FIG. 4 represents a working crown reinforcement (3) formed by two plies (31) and (32). The working ply (31) radially closest to the axis of rotation, is formed by several metallic steel cables individually wrapped in a rubber mixture B ,, which, in the example described, has a very extensive extension module. high since between 15 MPa and 30 MPa, and Mooney viscosity similarly high, between 65 UM and 95 UM. Radially inside is the first calendering layer or support layer Ai. consisting of a single rubber mixture of composition and properties identical to the composition and properties of the coating mixture B _t . Radially outside, there is the second calendering layer D consisting of several zones of mixtures of different composition and properties:

a central zone Dj, of axial width 1 of between 70% and 90% of the axial width L _s common to the two working plies (31) and (32), is made up of a mixture of high modulus, between 15 MPa and 30 MPa. and with a viscosity of between 65 MU and 95 MU, a mixture which is therefore identical to the mixtures constituting the support layer A \ and the coating B] of the cables;

- two lateral strips D2, in the described case of identical width, and made of a rubber mixture with relatively low modulus since between 3 MPa and 9 MPa, and of Mooney viscosity between 50 UM and 85 UM.

As for the working crown ply (32) radially further from the axis of rotation than the ply (31), and with an axial width less than said ply (31), it is of identical constitution to that of the ply ( 31), but the support layer A \ is then radially situated outside the ply and the three zones D] and D2 of the layer D are radially inside said layer D, so that the said three zones of the ply (32) are located opposite the three zones of the first ply (31), in particular the lateral zones D2 of a mixture with low elasticity modulus, which makes it possible to greatly reduce the thickness of the rubber wedge (12) disposed between the two edges of the plies and placing it in the form of flat strips.

The manufacture of the tire, in accordance with the invention, requires several preliminary stages before the vulcanization of said tire, and in particular the making or manufacture of the so-called "one-side calendered ply". In Figure 5 is shown a set of coils (100) on which are wound the metal cable for use in the web to be made. Several cables are directed to an extruder (200), the head of which has several dies, suitable for coating the said cables with the coating mixture layer (B, \) at a predetermined thickness. Said coated cables are then directed towards a tool, in this case a grooved roller (210), making it possible to separate each cable of the axially adjacent cable by the distance or not desired, then towards a calender (300) with two rollers (310) and (320). A quantity of rubber mixture intended to constitute the support layer (A, Ai) of the "calendered sheet on one side", initially preheated to a temperature making it possible to soften said mixture without, however, vulcanizing or pre-vulcanizing, is introduced between the two rollers ( 310) and (320). The passage between the two rollers leads to the production of a flat mixing strip, on which the coated cables will come into contact with the radially upper part of the upper roller (320). An auxiliary roller (330) known as a pressure roller, makes it possible to apply, if necessary, a given pressure on the cables, pressure regulated as a function of the desired depth of embedding of the cables in the flat strip A. A roller (340) deposits correctly an anti-adhesive interlayer strip, generally made of polyethylene, either on the side where the coated cables appear, or on the opposite side, so as to be able to wind, as known per se, the "calendered sheet on one side" on a roller (350 ) winding, intended to supply the cutters and tablecloth preparation tables, the reinforcing elements being in the direction of the length of the tablecloth.

As known per se, the "calendered sheet on one side", depending on whether it is to prepare a width for carcass ply or a width for crown ply, is cut either perpendicular to the common direction of the reinforcing elements, or with a certain angle α with respect to said common direction of the reinforcing elements, angle α which will be, in the finished tire, the angle of the elements with respect to the circumferential direction of said tire. The widths thus obtained are then assembled, abutted, either end to end in the case of metallic reinforcing elements, or with overlap from one edge to the other in the case of textile reinforcing elements. . In the case of a butt joint, this can be done by adding a small flat layer of rubber called bonding, placed on the junction or placed on one edge and then pass under the other edge . The widths thus assembled form the "one-side calendered ply" ready to be used for example on the means of manufacturing the unvulcanized and partial tire blank. The complete production of the carcass ply is done, for example, by laying the "calendered ply on one side" on the different layers of rubber mixes and different bead reinforcement plies predisposed on the cylindrical drum for making the blank carcass cylindrical, so that the support layer A is arranged radially inside. On the apparent reinforcing elements of the "calendered sheet one side" are then placed the various circumferential layers Ci, C2, C3 ..etc ...., necessary to form the outer layer C of calendering, said layers being, at the unvulcanized state, of thicknesses chosen to obtain the desired thicknesses in the vulcanized state, taking into account the rate of conformation of the carcass blank transforming said cylindrical blank into a toroidal carcass reinforcement blank. The finishing of the carcass ply being carried out on the cylindrical confection drum, the next steps of said confection are the usual steps and known per se: installation of rods for anchoring the carcass ply, installation of the various filling rubber fillings of bead, border erasers or others, turning the edges of the carcass ply around the rods and stuffing, etc.

The production of a complete crown ply (31) is also finished in the same way, that is to say on a drum for manufacturing an unvulcanized tire blank: after fitting, on an unvulcanized blank and toroid of carcass reinforcement, different layers (8) of rubber mixes radially separating the carcass reinforcement (1) from the crown reinforcement (3), is laid a "calendered sheet on one side", unvulcanized and formed reinforcing elements individually coated in a rubber mixture B \, having a given composition and properties, the so-called reinforcing elements arranged parallel to each other being covered on one side with a first rubbery layer A] or support layer, of constant composition and properties, said "one-side calendered ply" being brought into contact with a second calendering layer D of variable composition and properties as a function of the axial width of the crown ply (31) in the tire. As for the manufacture of a working crown reinforcement (3) with two plies (31) and (32), it is possible to place on the layers (8) a first "one-side calendered ply", the support layer Ai of said ply being radially inside, then, on the visible reinforcing elements of said first "one-side calendered ply" are laid the various layers of rubber mixture D \ and D2 forming the second calendering layer of said first crown ply (31), radially closest to the carcass reinforcement. The manufacture of the second crown ply (32) is carried out in an identical manner, but starting with the laying of the layers D \ and D2, which are then covered radially with a second "calendered ply on one side", presenting themselves so that the apparent reinforcing elements of said second ply are radially inside said ply.

The finishing and vulcanization of the toroidal tire blank are then continued in the usual and known manner.

Claims

1 - Tire having at least one reinforcing ply (1. 31, 32) consisting of reinforcing elements embedded in vulcanized rubber, characterized in that the reinforcing elements of said ply are individually coated in a rubbery mixture (B, Bj), said coating mixture, having a given composition and physical properties, the said reinforcing elements arranged parallel to each other being covered on one face with a first rubbery layer (A, Ai), called the first calendering layer, of constant composition and properties, while said elements are covered on the opposite face with a second rubbery calendering layer (C, D) of variable composition and properties as a function of the meridian position on the ply in the tire.

2 - A tire according to claim 1, characterized in that the composition and properties of the first layer (A, Ai) are identical to the composition and properties of the coating mixture (B, B}) of the reinforcing elements of the ply.

3 - A tire according to claim 2, characterized in that the reinforcing ply is a ply (1) of carcass reinforcement.

4 - A tire according to claim 3, characterized in that the ply (1) of carcass reinforcement, in its main part on its external face and in its part turned over on its axially internal face, is calendered with the first layer A of constant composition and properties, while the opposite faces are covered with the second calendering layer C of variable composition and properties as a function of the meridian length of the ply (1) in the tire.

5 - A tire according to claim 4, characterized in that the coating mixture B has the same composition and properties as those of the mixture of the first calendering layer A, the secant modulus of elasticity in tension of said mixture in the state vulcanized, measured under a relative elongation of 0.1, being between 6 and 12 MPa, while the Mooney viscosity of said mixture in the unvulcanized state is between 60 MU and 90 MU.

6 - A tire according to claim 4, characterized in that the second layer C is formed:

* of a first strip Cj of rubber mixture, going from the point T of the rod (2) radially closest to the axis of rotation, at the point S of intersection between the mean axis of the meridian profile of the ply of carcass (1) and the perpendicular to said lowered profile of the end of the lap (10) of ply (1), the TS zone being called bead zone,

a second strip C2 of rubber mixture, going from said point T to point R representing the end of the upturn (10) of the carcass ply (1), the area TR being called the upturn area,

* of a third strip C3 of rubber mixture, between point S and a point N, of intersection of the mean axis of the meridian profile of carcass ply (1) with a straight line parallel to the equatorial plane and distant from said plane d '' an amount which may be between 30% and 45% of the axial width of the tread (9), the zone SN being called the flank and shoulder zone, * a fourth band C4 of rubber mixture, between point N and the equatorial plane XX ', forming the so-called apex zone, the bands Ci, C2 and C4 being made of the same mixture whose elasticity modulus is between MPa and 12 MPa and whose Mooney viscosity is between 60 UM and 90 UM, whereas the C3 band consists of a mixture whose elastic modulus is between 3.5 MPa and 5 MPa and whose Mooney viscosity is between 55 CU and 75 CU.

7 - A tire according to claim 2, characterized in that the reinforcing ply is a ply (31, 32) of crown reinforcement (3), formed of reinforcing elements parallel to each other in said ply and forming with the direction circumferential of the tire an acute angle, the meridian position being judged on the axial width of said ply (31, 32).

8 - A tire according to claim 7, characterized in that it comprises a crown reinforcement (3) formed of at least two working crown plies (31, 32), the ply (31) radially closest to the carcass reinforcement being calendered on its radially inner face with a first calendering layer A \ of constant composition and properties, and on its radially outer face with a second calendering layer D of composition and variable properties depending on the width axial of said ply (31), while the ply (32) radially outside the ply (31) is calendered on its radially outer face of the first calendering layer A \ of constant composition and properties and on its face radially inner of the second calendering layer D of variable composition and properties as a function of the axial width of said ply (32).

9 - A tire according to claim 8, characterized in that the rubber mixture constituting on the one hand the first calendering layer A \ and on the other hand the coating mixture B] of the reinforcing elements of the crown ply (31, 32) has, in the unvulcanized state, a Mooney viscosity of between 65 MU and 95 MU, and in the vulcanized state a secant modulus of elasticity under tension, measured at 10% relative elongation, between 15 MPa and 30 MPa.

10 - A tire according to claim 9, characterized in that the second calendering layers D are at least formed of three zones, a central zone D], consisting of a rubber mixture having in the vulcanized state a high modulus of elasticity under tension, between 15 MPa and 30 MPa, and in the unvulcanized state, a Mooney viscosity between 65 UM and 95 UM, and two lateral zones D2 made of a rubbery mixture having in the vulcanized state a low modulus d elasticity under tension, between 3 MPa and 9 MPa, and in the unvulcanized state, a Mooney viscosity between 50 and 85 MU.

11 - A tire according to claim 1, characterized in that the composition and properties of the first layer (A, A]) are different from the composition and properties of the coating mixture (B, B j) of the reinforcing elements of the ply .

12 - A tire according to claim 11, characterized in that the reinforcing ply is a ply (1) of carcass reinforcement.

13 - A tire according to claim 12, characterized in that the ply (1) of the carcass reinforcement, in its main part on its external face and in its part turned over on its axially internal face, is calendered with the first layer A of constant composition and properties, while the opposite faces are covered with the second layer C of calendering variable composition and properties as a function of the meridian length of the ply (1) in the tire.

14 - A tire according to claim 13, characterized in that the coating mixture B in the vulcanized state has a modulus of elasticity between 27 MPa and 45 MPa and in the unvulcanized state a Mooney viscosity between 70 UM and 100 UM, while the modulus of elasticity in the vulcanized state of the mixture of the first calendering layer A is between 10 MPa and 15 MPa and a Mooney viscosity in the unvulcanized state between 60 UM and 90 UM .

15 - A tire according to claim 4, characterized in that the second layer C is formed:

* of a first strip Ci of rubber mixture, going from the point T of the rod (2) radially closest to the axis of rotation, at the point S of intersection between the mean axis of the meridian profile of the ply of carcass (1) and the perpendicular to said lowered profile of the end of the lap (10) of ply (1), the TS zone being called bead zone,

* of a third strip C3 of rubber mixture, between point S and a point N, of intersection of the mean axis of the meridian profile of carcass ply (1) with a straight line parallel to the equatorial plane and distant from said plane d '' a quantity which may be between 30% and 45% of the axial width of the tread (9), the zone SN being called the flank and shoulder zone, a fourth strip C4 of rubber mixture, between the point N and the equatorial plane XX ′, forming the so-called apex zone, the strips C2 and C3 being made up of the same mixture whose elasticity modulus is between 3, 5 MPa and 5 MPa and whose Mooney viscosity is between 55 UM and 75 UM, while band C] consists of a mixture whose elastic modulus is between 10 MPa and 15 MPa and whose Mooney viscosity is between 60 UM and 90 UM, and that the band C4 is made up of a mixture whose elastic modulus is between 6 MPa and 12 MPa and whose Mooney viscosity is between 60 UM and 90 UM.

16 - A tire according to claim 12, characterized in that the ply (1) of carcass reinforcement, in its main part on its internal face and in its part turned over on its axially external face, is calendered with the first layer A of constant composition and properties, while the opposite faces are covered with the second calendering layer C of composition and variable properties as a function of the meridian length of the ply (1) in the tire.

17 - A tire according to claim 16, characterized in that the coating mixture B in the vulcanized state has a modulus of elasticity between 27 MPa and 45 MPa and in the unvulcanized state a Mooney viscosity between 70 UM and 100 MU, while the modulus of elasticity in the vulcanized state of the mixture of the first calendering layer A is between 3.5 MPa and 5 MPa and the Mooney viscosity of said mixture A in the unvulcanized state is between 55 CU and 75 CU.

18 - A tire according to claim 4, characterized in that the second layer C is formed: * of a first strip C \ of rubber mixture, going from the point U of the upturn (10) of the carcass ply (l), located substantially halfway up said upturn (10) at the point S of intersection between the axis by means of the meridian profile of the carcass ply (1) and the perpendicular to said lowered profile of the end of the ply upturn (10),

* a second strip C'2 of rubber mixture, going from said point U to point R representing the end of the upturn (10) of the carcass ply (1),

* of a third strip C3 of rubber mixture, between point S and a point N, of intersection of the mean axis of the meridian profile of carcass ply (1) with a straight line parallel to the equatorial plane and distant from said plane d '' a quantity which may be between 30% and 45% of the axial width of the tread (9), the zone SN being called the flank and shoulder zone,

* a fourth band C4 of rubber mixture, between point N and the equatorial plane XX ', forming the so-called apex zone, the bands C'2 and C'3 being made of the same mixture whose elasticity modulus is between 3.5 MPa and 5 MPa and whose Mooney viscosity is between 55 UM and 75 UM, while the band C'i consists of a mixture with a modulus of elasticity between 10 MPa and 15 MPa and whose Mooney viscosity is between 60 MU and 90 MU, and that the C'4 strip consists of a mixture whose elastic modulus is between 6 MPa and 12 MPa and whose Mooney viscosity is between 60 MU and 90 MU.

19 - A tire according to claim 1, characterized in that the reinforcing ply is a crown reinforcement ply formed of circumferential elements. 20 - A tire according to claim 1, characterized in that the reinforcing ply is a bead reinforcing ply.

21 - A tire according to claim 1, characterized in that the reinforcement ply is a sidewall reinforcement ply.

22 - Method for manufacturing a tire according to one of claims 3 or 12, consisting first of all of making on a drum an unvulcanized cylindrical blank of carcass reinforcement comprising at least one carcass ply (1), characterized in that, after the carcass ply (1) has been made, after the different layers of rubber mixes and different bead reinforcement plies have been laid on the cylindrical drum for making the cylindrical carcass reinforcement blank laying of an intermediate product called "one-side calendered sheet", unvulcanized and formed of reinforcing elements individually coated in a rubber mixture B, said coating mixture, having a given composition and physical properties, the said reinforcement arranged parallel to each other being covered on one face with a first rubbery layer A, called the first layer of calandrag e or support layer, of constant composition and properties, said "calendered sheet on one side" being brought into contact with a second calendering layer C of composition and variable properties depending on the position along the meridian length of the sheet (1) in the tire.

23 - Method according to claim 22, characterized in that the unvulcanized "one-sided calendered sheet" is used with reinforcement elements individually coated in a non-vulcanized rubber mixture B. 24 - Process according to claim 23, characterized in that the unvulcanized "one side calendered sheet" is used with reinforcement elements individually coated in a rubber mixture B prevulcanized at a given temperature using a heating means adapted.

25 - Method according to one of claims 22 to 24, characterized in that the contacting is carried out by laying, on the different layers of rubber mixtures and different layers of bead reinforcement covering the cylindrical drum for making the cylindrical blank for the carcass reinforcement (1), of "the one-side calendered sheet" of coated reinforcing elements, and laying it on the visible coated elements of the "one-side calendered sheet" of the second calendering layer C of variable composition and properties as a function of the meridian length of the ply (1) in the tire.

26 - Method according to one of claims 22 to 24, characterized in that the contacting is carried out by laying, on the different layers of rubber mixes and different layers of bead reinforcement covering the cylindrical drum for making the cylindrical carcass blank, of the second calendering layer C of variable composition and properties as a function of the meridian length of the ply (1) in the tire and laying on said second layer of "calendered ply one side" of elements coated reinforcement, said elements being placed on the second layer C.

27 - A method of manufacturing a tire according to claim 7, consisting at a given time of placing on a toroidal blank of carcass reinforcement (1) not vulcanized a crown ply (31, 32) of parallel reinforcing elements between them in the sheet and making an acute angle with the circumferential direction, characterized in that the making of the sheet of crown (31, 32) requires, after laying on the toroidal carcass blank the various layers (8) of rubber mixes radially separating the carcass reinforcement (1) from the crown reinforcement (3), 'an intermediate ply called "one-side calendered ply", unvulcanized and formed of reinforcing elements individually coated in a rubbery mixture B 1, said coating mixture, having a given composition and physical properties, the said reinforcing elements arranged parallel to each other being covered on one side with a first rubbery layer A \ or support layer, of constant composition and properties, said "one-sided calendered sheet" being brought into contact with a second calendering layer D of composition and properties variable as a function of the axial width of the crown ply (31, 32) in the tire.

28 - Method of manufacturing according to claim 27 of a tire having a crown reinforcement (3) formed of two plies (31, 32) according to claim 8, characterized in that:

a) on an unvulcanized and toroidal blank for a carcass reinforcement (1), a "calendered sheet on one side", the support layer A] of said sheet being radially inside,

b) then on the apparent reinforcing elements of the "one-side calendered ply", the second rubbery calendering layer D of the radially inner crown ply (31), layer of composition and variable properties depending on the axial width of the ply in the tire, the layers Aj and D forming with the coated elements the crown ply (31) closest to the carcass reinforcement (1),

c) then the second rubbery calendering layer (D) of the crown ply (32) radially adjacent to the inner ply (31), layer of variable composition and properties as a function of the axial width of the ply (32) in the tire,

d) then radially on the outside, the "calendered sheet on one side" being so that the apparent reinforcing elements are radially on the inside.

29 - Method for manufacturing an unvulcanized “one-side calendered sheet” formed of reinforcing elements individually coated in a - preculcanized rubber mixture (B, Bi), characterized in that the reinforcing elements coming from coils of winding (100) are directed to an extruder (200) the head of which comprises several dies, adapted to coat the said elements of the layer (B, Bi) of coating mixture to a predetermined thickness, then directed to a means ( 210) making it possible to separate each cable from the axially adjacent cable of the desired pitch, in order to achieve a calender (300) with two rollers (310) and (320), making it possible to obtain a flat strip of support calendering mixture ( A, Ai), on which the coated elements will come into contact with the radially upper part of the upper roller (310), an auxiliary means (330) said pressing means making it possible to apply pressure to the es coated elements, pressure regulated as a function of the desired depth of embedding of the elements in the support layer (A, Ai) and a roller (340) depositing an anti-sticky interlayer strip on one of the faces of the sheet coming from of the calender (300), so as to be able to wind said ply on a winding drum (350), and then make the cuts at the desired angle, to form joined widths and obtain the "calendered ply on one side".